CPT code 39599: Diaphragm procedure, unlisted service2026 Medicare rate & RVUs in California

CMS doesn’t publish an office rate for 39599 in California.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 39599 covers

CPT 39599 is used for a surgical procedure on the diaphragm that no more specific CPT code describes. It does not identify a particular technique, defect, or extent of work. A surgeon may report it for a diaphragm operation that has no dedicated code. The operative report should describe the procedure performed, its clinical purpose, and the work involved so the Medicare contractor can evaluate the claim.

For Medicare physician fee schedule purposes, 39599 has status C: CMS publishes no national payment, and the Medicare Administrative Contractor prices each claim. The contractor sets the global period. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and the other procedures are paid at 50%. Report 39599 only when a more specific diaphragm code does not describe the work.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 39599 pays more and less in California

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

29 of 29 payment localities

How the 39599 rate is calculated

Each of 39599’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for 39599

The CMS indicators that decide how 39599 is paid alongside other services.

What modifiers do to the payment

When to use modifier 51

39599 compared with similar codes

How to choose

39501Diaphragm repairLaceration repair

39501 describes repair of a diaphragm laceration. Use 39599 only when the operation is not that defined repair or another specific diaphragm service.

39503Diaphragm hernia repairIncluding neonatal repair

39503 is for congenital diaphragmatic hernia repair in a neonate. 39599 is for a diaphragm procedure without a matching specific code.

39540Diaphragm hernia repairChronic traumatic hernia

39540 describes acute repair of a traumatic diaphragmatic hernia; 39541 describes the chronic situation. Use 39599 when neither defined service fits.

39560Diaphragm resectionSimple resection

39560 covers diaphragm resection with simple repair, while 39561 covers complex repair. Do not substitute 39599 when one of those defined resection services applies.

Codes related to 39599

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates